Find rustup components installed under a different toolchain #5
Description
In dtolnay/cargo-expand#39 I need to look for any rustfmt that may be installed on the system.
Currently what happens is that if the user has rustup component add rustfmt --toolchain stable but is running cargo +nightly expand, then somehow Cargo sets up the subcommand environment such that simply running Command::new("rustfmt") will end up running a shim that only tells you there is no rustfmt installed for the nightly toolchain. The thing is, I don't care whether the rustfmt I run is from the same toolchain as the cargo-expand binary. I would happily run the stable toolchain's rustfmt from the nightly toolchain's cargo-expand if I knew the path to the right binary.
pub fn find_installed_component(name: &str) -> Option<PathBuf>;Intended usage:
use std::process::Command;
let which_rustfmt = find_installed_component("rustfmt");
match which_rustfmt {
None => {
/* there is no rustfmt on any toolchain */
}
Some(rustfmt) => {
Command::new(rustfmt).args(...).spawn();
}
}This will be relevant to other Cargo subcommands too, so the implementation should go in a crate rather than directly in cargo-expand.